


Shelter

by The_Falling_Star



Category: Undertale (Video Game)
Genre: Alien Sex, Alternate Universe - Space, Double Penetration, F/M, Gender-Neutral Pronouns, Goopy W. D. Gaster, M/M, Mating Cycles/In Heat, Other, POV Second Person, Porn With Plot, Reader is gender neutral, Science Fiction, Tentacle Sex, Tentacles, Undertale Skeletons in Heat, Unreliable Narrator, Venom!Gaster
Language: English
Status: Completed
Published: 2021-01-03
Updated: 2021-01-03
Packaged: 2021-03-13 19:40:42
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 8,407
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28533819
Author URL: https://archiveofourown.org/users/The_Falling_Star/pseuds/The_Falling_Star
Summary: You are the lone technician aboard a cargo-ship embarking on a solo space mission. Eventual insanity is predictable on these long isolating journeys, but you never expected the voice in your head to have a name.He calls himself Gͭͪ̒̾͏̴͇̲̝͜͝ͅĄ̴̢̱̺̪̖͗̓͐̚͢S̛͎̬͈̗͑ͭͦ̂͟͢͞T͒ͣ̓̈҉͚̗̻̙͘͢͢E̛̍ͬͦ͛͏͟͏͎̯̯̣R̴̡̛̰̟̼̱͑͒͑̈͢
Relationships: W. D. Gaster/Reader
Comments: 16
Kudos: 131





	Shelter

**Author's Note:**

> Warning: This has some really dark shit, okay? If the filthy tags haven’t scared you off, just be aware there are _very_ questionable themes below. Sensitive readers, turn back now.

Deep space claimed all minds in the end.

You had known, from the moment you accepted this mission, your mind would fracture eventually. Humans were simply not fit to exist in a metal cage, isolated, alone, with nothing but the distant twinkling of stars and swirls of galaxies, and the steady hum of the ship’s engine. You too would one day succumb to the madness, despite all of the chemical intervention leaking through your veins.

You just didn’t expect it to happen so soon. 

You slipped down from your hammock, the micromesh situated above the engine’s core to keep you warm. Bare feet hit metal grating, and you hurried to pull on socks and boots before that lingering heat could be sapped from your limbs. Space was also _very_ cold, besides being very lonely. As the sole crew member to the massive cargo-hauler, your freight-class ship was enormous for just one human being. A lone worker ant navigating a maze of narrow metal halls.

The cycles you followed were nearly identical to one another. Wake. Exercise. Bathe in the tiny shower stall. Eat polystarch. Check ship diagnostics. Make necessary adjustments and repairs. Eat polystarch. Sleep. Wake for another cycle. 

You didn’t need to think about timing the endlessly repetitive rhythm of your life, the neuroregulator on your wrist did that. A small device implanted into your skin that sent electrical and chemical commands, spurred you to rest or to move, numbing your thoughts and keeping you calm. 

It was why you did not panic when you first heard the voice.

It spoke to you, in a language you did not know but could still somehow comprehend. It was soft and gentle, warmth and liquid heat dripping down along your spine as the whispered words wove about your brain, like dark smoke curling in your conscious.

_A̹̎n͖ͧd͖ͣ w̯͒h̩̓a͔̅t̤̽ d͚ͮo͎̔ ẅ͇́ȅ̟ h̦̄a͎ͭv̫ͮe͗ͅ h͕ͭe̬͋r͖̅ḙ͌?̞ͨ_

You froze, the magwrench in your hand stilling. You could not be sure where the voice had come from, but you had the distinct impression it was within your own head. You listened, waiting for more words.

A small part of you almost wanted to hear them. How long had it been since you’d heard anything besides the noises of the ship?

No further sounds besides the soft clicking of your magwrench were forthcoming, and so you completed your repair on the liquid oxygen condenser, put your tools back in their receptacle, and washed up before walking to the medbay to run a diagnostic scan on yourself. The bulky ring of sensors slowly panned down your body, transmitting a report to your tablet with a soft chime.

Everything appeared within normal range.

You continued on with your cycle. 

* * *

The voice returned the next cycle when you were scanning lines of logs, trying to find the timestamp of when the ship’s automated systems had recycled fuel cells. You should have received a notification to inspect the new cell, yet some trigger failed.

_A̬ͨn̥ͣ i̺͋ö͔n̲̚ e̤͗n̲̊g̗̾i̺̿n̝ͮẻ̻.̮͛ F͚̆ă̮s͇̏c̠͗i̻͐ṅ̠a̩̐t̟͋i͙͋n͎̔g̠ͭ.̳̐_ the odd, deep voice commented idly. 

From then on, the voice was a near constant companion. 

It seemed he was interested in more scientific related pursuits. The voice remarked on various aspects of the ship; air recyclers, hydraulic systems, onboard computers, anything and everything that had become mundane to you intrigued him, his voice becoming an increasingly frequent background noise.

Every one of your med scans showed nothing out of place.

Therefore, you must be losing your mind.

It was bound to happen. 

* * *

_I̫ͤs̩ͪ t͕̍h͉͐a̙̅t̫̔ w̲̋h͚̓ạ̈́t͉̉ c͇̔o͖ͦn̟͑s͈͑t͓̚i̗̅t͚̏u̥ͫt̬̍è̥š͓ a̜̎ś͖ y͋ͅo̩͆ȗ̖r̗͐ f̠̉ò̥ö̱́d͙ͭ?̦̂_ he asked with a hint of distaste as you added water to your polystarch powder, the dingy purple mash bubbling ferociously in an exothermic reaction and solidifying into a substance that had the texture of a dry sponge. You mechanically ate, the food nearly tasteless, but providing all the nutrients your body needed.

You decided you might as well respond for once.

“Yes.”

_A̗̒h̭͒,͍̄ s̤ͥo͙̒ y͓͋o̦͒u̩ͥ d͍̋o̹̅ s̯͊p̤ͬe̘͊a͈͂ḱ̦.̯ͨ_ he said with surprise in a tone that boarded on condescending, _A̦ͨn̤̅ḋ̯ ỷ͈ŏ̻u̥ͯ c̻̋a͖ͧn̥̋ u͉͌n͇̈́ḍ̽è̫r̥ͧs̠ͧṯͬa̻̽n͇͐d̩ͣ m͕͛e̠̐?͙̃_

“Yes.”

_Hͤo͗ẇ_ **_s͂p͊l͗e͐ňd͆iͥd́_** _.̄ T͌h̓i̅s͋ ĩs̀ a̾ f̂aͦr̚ m̒o͒r̓eͨ f̂äv͌o͑ȑaͩb͑lͣe̋ p̏oͮs̍s͑i̇b̈́i̊l͋ĩt͐y̆ t͊hͥaͭt͑ Ȋ c̏o̓u̔l̽dͩ h̃aͤv͗eͥ iͩṁa͑gͨiͭnͤëd̒.̒ Y̾o̽ũ aͥr̓ȅ õn͐eͭ o͂f̉ tͯh̿o͂s̿e͒ h̅uͪm̃a͒n͐ c̐r̔e̊a͌tͦũrͬe͗s̓,̂ c͐o̓r͐r̉ẻc͊t̏?́_

“...Yes.”

You weren’t sure what other option there could have been. 

“What are you?”

_Ā̘ l͗ͅo̗̓s̺̾t͖̄ s͓͑o͉ͣű̝l̩̓.ͤ_

You couldn’t articulate it if you had tried, but somehow you knew, you _felt,_ a smile curling in the dark, pleased words leaching through bared teeth, something crooning and sinister.

_B̓ūt̅ I͒ bͭe͐l͐ȉeͧvͣě I͛ h̓a̍v̀ë́ b͗ẻe̽ň f́őuͨn̐d̚.̈́_

* * *

Madness wasn’t so terrible, you decided. The voice kept you company. Odd, having someone to talk to after so long. Though, you weren’t the one doing most of the talking. Most of the time you were answering his questions, often as briefly as possible. The voice was distracting in regards to your daily duties and your efficiency, according to the ship’s computer, had decreased 2.3% since his initial introduction.

_D͂o̿ ỷoͦǘ h̾ä́vͦe̍ a̾ ñaͧmͤeͫ?́_ he asked as you reviewed a manual on how to complete a repair on the robot that preformed external tasks on the ship. The magnetic treads were malfunctioning, and it would not do well to have it drifting off into the endless black of space. You scrolled through schematics on a tablet with a swipe of your fingers, skimming over lines of documentation. 

“Yes.”

_Mͧy̿,̄ h̎oͩwͨ f̏o̅rͪt́h̒c̅o̒m̚i̋n̅gͯ w̄e͌ ȃr͊e̎! H̃e̋r͛eͯ,͐ i͋f́ I͐ p̉r̍o͂v̏i͒d́eͧ mͦǐn͂eͥ,̏ wͮi̚l͆l̉ t̋h̆a͆tͭ l͒ȍo̓s̀eͯnͥ y͗öu̅r̿ t͌o͑n͊g̀uͣe͐?ͭ Ȋ àm̀ c͐ăl̃l̎ȇd͊ G̔a͂s̔t̽eͯr̓.ͯ_

“You have a name?”

_Ȯf͐ c͛oͦu͂r̈́s͆ȇ,͛ w̓hͭy̌ w͐o̚u͛l̑dͣn͌’ͨẗ Ḯ?̎_

“You are me.”

_.̃.ͬ.̅I͌ b͋ēg͐ y̌ö́u̐rͨ pͮăr̊d̐o̊n̍?̌_ he said after an incredulous pause. 

“You are a hallucination from the stress of a solo deep-space mission. You’re a figment of my imagination. You shouldn’t have a name.”

_A͆n̓d͑ yͭëtͦ Iͯ d̔oͣ.̇_ he said, sounding almost offended, _I͆ cͮȃnͨ a͌s̍s͐uͯrͭē yͫȍu̿ Ȉ a̐m̒ n̋oͮt͗ jͨuͣs͛t͊ a̐ b̿yͭpͭrͬo̎d͂uͩc̀t̄ oͮf̂ ỳõuͤrͯ mͨi̅n̍d͆,͗ I͊ a̅m̅ a͂ bͮe̔i͆n͑gͭ ẅh̏o̓l̈lͥy̐ uͦńt̏o̽ m̋yͭs͛e̍l͊fͤ.ͣ.͒.̊W̋e͒l̾lͣ,́ pͬeͨr̒h̐a̍pͪs̄ n̄oͥt͂_ **_w̔h̃o͌l̎lͭy̎_** _,ͣ Iͤ a̋m̄ ün̋a̾b̿ľë́ t͗o͂ f̐òr̂m͂ aͫ p̄h͗yͪs̄iͭcͪa̓l͋ b̍oͮdͣȳ f͛oͤr͊ tͧh͂eͫ t̍ỉm͋eͦ b͆ẻi̋nͥg̓,̿ bͬu͛t̑ tͭh̑a͛t̋ sͮh͗aͬl̅l͋ b͊eͣ ċoͨr͆r͌eͦc̒t͂eͩdͣ i͛n̒ t̓hͨẻ n̐ẽa̾rͯ f̚u͆t̓u͑r̅e̔.̌_

You were graced with silence for approximately two minutes before he interrupted your reading again.

_Wͧh͌aͫt͒ i̋s̋ ỷoͤuͫr̀ m̉i̇sͮs̈i̎oͬnͩ,̃ e͑x̐aͣćt͋l̉y͑?͊_

“Deliver colonist supplies to Alpha Centauri, Proxima B.”

_T́h̆e͊r͛ȅ ỉsͬ a͆ c̎oͬl͑oͯn̄yͬ t̓hͦe̾rͤë́?̊_

“Not yet.”

_A͊ń o͌ŭṫp̉o̓s̔t̐?ͧ_

“No.”

_.̓.ͥ.̐Sͭȯ y̓óuͭ wͭi͗l̄l̾ b̊e͂ āl͒oͩnͮe͊.́_ he said, sounding very displeased with this obvious conclusion. 

“Yes.”

_Ȃn̚dͤ hͣǒw̐ ẘiͦlͫlͯ y̽o̿u͒ s̒ûrͥv̈́ȉv͛eͯ t̿ĥe̅r͆è?̚ W͂h̑a͛tͥ hͤȧṕp̔eͭn̋s͌ i͛f͆ yͫo̐ủ b̑e̓c̿oͪm̌eͥ iͦn͛jͪuͮr̓e̾d͌,̂ o̐r͗ y̓oͪu̚ e̾x͛pͨe̍rͧi̊ėn̉cͮě c͛åtͪaͥs̆tͬr̒ōp͒hͤi̚c͗ ẻq̄u͛i͊p̿m̅e̚nͮt̄ f̌a̽iͪl̂u̓r̂ë?́_

“...I have a mission to complete.”

_Hͭo̔w͗ dͥo͗u͌rͪ.̓ F̓oͤr̒g̅i͛v̀e͂ m͗e̐,̿ b̂ȗt͌ I͆ f̽e̊e̓l̽ ẗhͭiͩsͩ m͗iͪsͩsͦīo̅n͌ ḯs̎ qͩu͆ĩt͊eͦ ă wͫaͬs̃t̓e͐ o͆f͆ y̒öǔrͫ pͦo̓t̑eͤn̋t͌ḯa͛l͌...Wͨa̓i͌t̊,̓ s̒c̒r͊o̽ľlͨ b̀a̐c̚k͑ tͤȏ t͌ĥeͥ p̚r̆ȇv̑i͂ȯuͫs̀ sͦe͛cͣtͮíoͨn̑.̊_ he commanded.

You were about to object, this was your work, not some leisurely read after all, but your fingers moved of their own volition across the tablet, the lines of text sliding back. 

You tried to advance to the next page again.

Your fingers failed to obey.

“What?--”

_T̑h͋eͥr͌e͊,̏ t͊h́e̎ s̾o͊lͬd̔e͑ȑi͑n͗g̽ őn̓ ẗh̐è p͒r̎īm̄a̔r̓y̎ cͥïr̔c̒uͭĭtͭ b̿ǒa̍rͮd͛.̓_ he said, and your fingers pointed to the corresponding section of the schematic, _I͛ d̏oͦ n̄õtͧ b͐e̽l͐îe̒v̎ȇ t̿h͒eͪ m̽a͆t͛ėrͤi͂aͥl̉ uͭs̈́e͒d̊ ís̎ ča̓p̌äbͯl̓ĕ o͑f̆ w͐īt̐h͆s̃tͮa̚n̆dͧi̓nͯg̽ s̔ȗbͬṡt̑ànͪtͫi͒a̒lͣ t̊e̍mͤp͂ěrͪȁt̂u̓rͩe̍ v͋a͂r̀íât͆i͛ȏn̅s͐.̂_

“My hand-”

_A̎h̉,͌ ŷo͒u̚ m̆aͨy̏ u͑s̓e̾ i̓tͯ a͒gͦa͊i̓n̅.ͣ_ he said casually, and you flexed your fingers, once more the digits conceding to your will.

“You controlled me.”

_Iͦ dͪĭd̅,̇ y̌ěs͆.́_

“How?”

_Ĩ ămͥ iͮn̍s͌i͌dͧeͪ ẏoͣu̔.ͭ Y̓òu̇ ȁr͛e̓ m͗y̐ h͊o̾sͧt̿.̑ T̎h̄ĩsͭ b̐oͪd̋ÿ́ i̋s̊ m͛iͫn̓ē a͋s͌ mͧùċhͫ a̐sͥ i̿t̐ iͭsͫ y̓öu͌r͗s̒.̈́_

That was unsettling. Perhaps the voice was not as comfortable a companion as you had originally thought. Your neuroregulator illuminated with a red indicator and after a second or two, you felt significantly more relaxed. Instead of panicking, you found yourself curious, asking questions of him for once.

“How did you know about the circuit board?”

_Ǐ f͂a͑n̏c̉iͧe̽d͌ m̈́ȳs͗e̍l̽f̌ sͪo̓mͦeͪt͐hͦiͯṅgͤ o̒f̾ a͌n̆ aͬdͤe̾p̍t͗ e͆n̾gͥi̒n͗ȇeͦṙ ỉn̋ mͨy̓ pͣa͗ṡt͗ lͩiͧf̂è.̽_ he answered, almost smugly. 

“Were you always like this?”

_L̒iͬk̚e̒ wͨh͐a͑t́?̎_

“Just a voice.”

_“J͌u͒sͦṫ”!? O͒h̓,͋ s̈wͬe̊eͪṫ l̂iͭtͫtͩlͦe͂ t͐h̎ĭn͛g̓ y̐oͣu͆ ảrͣe̍,͐ Iͦ a̚m̑ fͣa͊r͊ m̀o͗r͂e̍ tͬh̅aͨń y̓oͮuͬ c̍ȕr̂r̅eͮnͤt͒l̏ẏ u̓nͤd̓e͗r̐s͒tͭǎn̍dͧ.ͧ Yͯo̔u̓ wͧi͂l̅l̓ cͤo͒m̿eͮ tͤoͬ lͭeͪår̃n̓ t̐h̓e̾ f̔uͩl͊l̊ e͒xͭt̓e͌n͂t̃ oͮfͥ m͆e͆ iͫnͨ t̋i̅mͣeͩ.̃ Bͥuͮt̎ tͫoͫ a͐ṅs̅wͪeͣr̎ yͤoͦũr͐ q̚u̎e̊sͯt͐íoͭn̓,̚ nͩo̓.̉ I̐ w̏a͗s̒ n͂o̊tͥ a̽lͥẃăẙs̽ l̀îk̅e͒ t̋h͛i̚s̐.̐ M̅ȳ b̾o̓dͩy͊ ẇa͌s̾ ḃȓo̓kͭȅn̏.ͭ S͗h͊aͧt͛tͤe̚r̂e̿d̆ a̽c͐r̄o̍s̀sͤ s̆p̈ä́c͗e͊,ͩ r̓e̚nͦd̒eͧrͩi̅n̒gͧ mͩeͯ a̚ šh͛a̋dͪē.̍ Iͣ r̉eͥq͑uͥiͭȓe͑ à b̀e̅ìn̚gͭ s̍uͣc̉h͋ a͌s̍ yͩoͬu̔r̈šȇl̚f̅ t̓oͤ s̀èŕv̂eͯ a̓s̾ aͯ hͨo̓s̃tͪ.̅ Ònͩeͯ m̍ĭg͆h̊t͗ eͧvͫe͛n͌ c̍a͌l̑l̃ m̂e̋ ȁ p̓a̓rͫaͭsͪȉt͆ĕ,̅ t͋h̃oͦu̾ḡhͤ Iͩ pͪr̓e͊fͫër͌ t̑oͭ t̄h̒iͥnͭkͯ oͧf́ t̒hͫiͮs̊ åsͨ a͑ mͦoͭȑë́ sͮyͯm̆b̐īŏt̉ĭc̋ rͫe͆l͗a̋t͆iͭŏnͩs̄hͩi̇p̎.ͧ_ His voice lowered, a dark purr, shadow-soft and smoother than silk slinking through your mind, _Ȋ t̒h͌ìn̿k͛ y̎òu͐ w͑iͧlͯl͂ f̓i̍n̋ď tͤh̒e͌r̈e̿ ȧr̒eͬ bͥeͯn̍eͯf̄i͂tͥs̏ t̓o͗ k̽e̋e̊pͪiͮnͫgͩ m̏y̾ c͗ö́m̌ṗa͂nͯy͗.̍_

* * *

If the voice was a hallucination, it was a very elaborate one your mind had constructed. 

Gaster had his own personality and knowledge outside of your own. This made very little sense, yet despite the near daily scans to try and find some sort of anomaly that would explain how the being came to be (outside of the loss of your sanity) there was absolutely nothing amiss. You poured over the latest one, having subjected yourself to every diagnostic the ship was capable of.

_S̐t͆o̽p̐.̏_ He ordered as you scrolled further into the latest report, and you of course had no choice but to obey. He was silent as he, presumably, read over your scan.

_W̆h͑aͬẗ́ aͭrͯeͨ t̊hͨēs͌é?̽_ he demanded, pulling up an image of a soft tissue scan and pointing with your own hand to pale masses amidst your organs.

“Tumors.”

_T̿u̎mͨoͤr͆s͋?ͧ_ he echoed. You couldn’t place his tone. It was almost soft. Incredulous. Dismayed perhaps?

“Cancer.”

_I̍sͫ t̉h̑aͬt͐ w̿hͪy̆ ȳoͦȗ’̅v͐e̊ eͭmͭbͩa̐r̋k̍édͫ o͌nͤ t̔hͧi̓sͮ s̓u͒iͮc̒ḯd̈́e̿ mͤi̓s̅s̆ïoͨnͥ?͑ B̉e̍c̾aͪu͒s̓eͥ y͌o̍uͪrͣ c̈ȯn̔d̈́īṫiͭoͦn̑ ẇäsͥ t̐e͂r̍m͆i͊ǹaͮl̊?̌_

“No. They are _from_ my mission. Sleeping above an ion engine has consequences.”

_I͚̔t̠̆ ĩ̖s͍ͮṅͅ’͚̇ṱ̓ p͔̎r͓͗o̫̍p̲ͩe͇ͭr͉̓l͓ͪy̪ͪ ś̯h̻ͭǐ̲ẻ͇ḽ͐d̻͐ĕ̺d͔͂!͍ͩ?͙̑_ he _yelled_ , and you winced as he raised his voice for the first time.

“No. It would interfere with the thermal regulation of the ship, and the additional weight would require extra fuel cells.”

_.̃.̇.̿T̓h̐īsͥ i̋s͗ m̐a̔d̃n̐ĕs̒sͥ.̾ Tͩhͩiͨs̐ iͯsͬ_ ** _ủn̈aͭcͩcͭe̊p͒t̆aͯb͛lͨeͨ.͂_** He sounded _furious._

“Their growth is regulated enough and the pain manageable so I will be able to complete the mission.”

_T̒o̅ h̾e͊lͨl͐ wͧi̔t̊h́ y͗őuͫrͮ ṁïsͣs̈i̍oͨn͊!̔ Nͭo̔,̈ t̓h̒i͋s̽ w͒i͆l͑l̊ n͂o͒t͒ h́aͣp̈́p̎ẻn͒ t̿o̔ y̽o̿uͤ.̒_ **_Ī w̌ȉlͬl̈ n̔oͯt̚ a̋lͩlͯo͊w̐ tͭh̍iͨs͒.ͯ_ **

You shrugged. 

“It’s too late.”

What could a mere voice do?

* * *

_A̍h̍,̍ I̍ h̍a̍v̍e̍ s̍o̍m̍e̍t̍h̍i̍n̍g̍ t̍o̍ s̍h̍o̍w̍ y̍o̍u̍.̍_ Gaster said excitedly as you exited the shower stall a few cycles later. Showering was probably the most uncomfortable everyday occurrence, with non-existent water pressure, the trickle of lukewarm liquid timed to precisely three minutes. Only enough time to scrub your skin and rinse off, and by the end you were shivering as you pat yourself dry with a small sheet of absorbent microfiber. 

“Can’t it wait until I’m dressed?”

_T̍h̍a̍t̍ w̍o̍u̍l̍d̍ d̍e̍f̍e̍a̍t̍ t̍h̍e̍ p̍u̍r̍p̍o̍s̍e̍.̍ H̍a̍v̍e̍ a̍ l̍o̍o̍k̍ i̍n̍ t̍h̍e̍ m̍i̍r̍r̍o̍r̍.̍_

You walked over to the tiny sink, staring at the small mirror that afforded you a limited view of yourself. Immediately you took note of what Gaster wanted you to see; Lines of black in the outline of your veins covered your torso, crept up your neck, your jugular and carotid artery drawn in pitch-colored lines. 

Your fingers reached up, tracing over your skin, trying to judge if what you saw was real, or another trick of your mind. You glanced down at your forearms, the same black veins visible there too. 

_D̍o̍ y̍o̍u̍ t̍h̍i̍n̍k̍ m̍e̍ a̍ m̍e̍r̍e̍ v̍o̍i̍c̍e̍ n̍o̍w̍?̍_ he said in a self-satisfied tone.

You did not answer, instead hurriedly grabbing your jumpsuit, zipping up the thick material that kept you warm in the cold ship. You dashed down to the medbay, doing your best to keep still as you initiated another scan, impatiently awaiting the results.

All readings normal.

...Better than normal.

Your tumors had shrunk. 

“How is this possible?”

_I̍ a̍m̍ r̍e̍p̍a̍i̍r̍i̍n̍g̍ y̍o̍u̍r̍ b̍o̍d̍y̍.̍_

“Why?”

_W̍e̍l̍l̍,̍ I̍ b̍e̍l̍i̍e̍v̍e̍ w̍e̍ h̍a̍v̍e̍ a̍l̍r̍e̍a̍d̍y̍ d̍i̍s̍c̍u̍s̍s̍e̍d̍ t̍h̍a̍t̍ y̍o̍u̍ a̍r̍e̍ p̍l̍a̍y̍i̍n̍g̍ h̍o̍s̍t̍,̍ a̍n̍d̍ I̍ h̍a̍v̍e̍ a̍ v̍e̍s̍t̍e̍d̍ i̍n̍t̍e̍r̍e̍s̍t̍ i̍n̍ k̍e̍e̍p̍i̍n̍g̍ y̍o̍u̍ a̍l̍i̍v̍e̍.̍ B̍u̍t̍ b̍e̍y̍o̍n̍d̍ t̍h̍a̍t̍.̍.̍.̍Y̍o̍u̍ a̍r̍e̍ i̍m̍p̍o̍r̍t̍a̍n̍t̍ t̍o̍ m̍e̍.̍ P̍e̍r̍h̍a̍p̍s̍ t̍h̍e̍ m̍o̍s̍t̍ i̍m̍p̍o̍r̍t̍a̍n̍t̍ b̍e̍i̍n̍g̍ a̍m̍o̍n̍g̍ a̍l̍l̍ t̍h̍e̍ s̍t̍a̍r̍s̍.̍_

* * *

You were healing.

Not just the cancerous growths in your body, but small pains you had grown numb to with the neuroregulator administering doses of painkillers on a regular basis. Your back didn’t twinge when you hunched in small spaces making repairs, the frequent nicks and cuts on your hands disappeared a day after inflicting them upon yourself, and when you slept it was more deeply and restorative than ever. 

_I̍ c̍a̍n̍’̍t̍ t̍a̍k̍e̍ a̍l̍l̍ t̍h̍e̍ c̍r̍e̍d̍i̍t̍,̍_ he said after you pointed it out to him, _I̍ a̍m̍ d̍r̍a̍w̍i̍n̍g̍ s̍t̍r̍e̍n̍g̍t̍h̍ f̍r̍o̍m̍ y̍o̍u̍ a̍s̍ w̍e̍l̍l̍.̍ W̍e̍ a̍r̍e̍ f̍e̍e̍d̍i̍n̍g̍ i̍n̍t̍o̍ e̍a̍c̍h̍ o̍t̍h̍e̍r̍.̍ I̍ m̍a̍y̍ s̍o̍o̍n̍ b̍e̍ c̍a̍p̍a̍b̍l̍e̍ o̍f̍ p̍h̍y̍s̍i̍c̍a̍l̍ i̍n̍t̍e̍r̍a̍c̍t̍i̍o̍n̍ o̍u̍t̍s̍i̍d̍e̍ o̍f̍ y̍o̍u̍.̍_

“Still, thank you for helping me.”

_H̍m̍,̍ p̍e̍r̍h̍a̍p̍s̍ i̍n̍ t̍h̍e̍ f̍u̍t̍u̍r̍e̍ y̍o̍u̍ w̍i̍l̍l̍ n̍o̍t̍ b̍e̍ s̍o̍ q̍u̍i̍c̍k̍ t̍o̍ e̍x̍p̍r̍e̍s̍s̍ g̍r̍a̍t̍i̍t̍u̍d̍e̍.̍_ he thought aloud, and no matter how you asked what he meant, he would not elaborate on that cryptic statement.

* * *

Your hands moved on their own, guided by the being inhabiting your body. Gaster was recalibrating the sensors on the robot, just to see if he could. He would walk through the documentation flawlessly, then confirm with you he’d done the work to your satisfaction (you felt it was with a touch of a condescending air) before moving on to the next sensor. You could only watch, unable to reassert control over your own limbs once he decided to entertain himself this way.

You were a passenger in your own body.

That should have been horrifying. 

_W̍h̍y̍ d̍o̍ y̍o̍u̍ n̍o̍t̍ f̍e̍a̍r̍ m̍e̍?̍_ he asked as the last sensor passed the self-tests, as if journeying down your same trail of thoughts, _H̍e̍r̍e̍ I̍ h̍a̍v̍e̍ c̍o̍m̍p̍l̍e̍t̍e̍ c̍o̍n̍t̍r̍o̍l̍ o̍v̍e̍r̍ y̍o̍u̍r̍ m̍o̍t̍o̍r̍ f̍u̍n̍c̍t̍i̍o̍n̍s̍,̍ y̍e̍t̍ f̍o̍r̍ a̍l̍l̍ t̍h̍e̍ t̍e̍r̍r̍i̍b̍l̍e̍ t̍h̍i̍n̍g̍s̍ I̍ c̍o̍u̍l̍d̍ d̍o̍,̍ y̍o̍u̍ n̍e̍v̍e̍r̍ f̍e̍a̍r̍ t̍h̍o̍s̍e̍ p̍o̍s̍s̍i̍b̍i̍l̍i̍t̍i̍e̍s̍.̍_

“I don’t get scared anymore.”

_A̍h̍,̍ y̍e̍s̍.̍ T̍h̍i̍s̍-̍_ your fingers twitched of their own accord, grazing over the neuroregulator, _c̍o̍n̍t̍r̍o̍l̍s̍ y̍o̍u̍.̍ I̍ h̍a̍v̍e̍ b̍e̍e̍n̍ c̍o̍n̍s̍i̍d̍e̍r̍i̍n̍g̍ t̍h̍i̍s̍ d̍e̍v̍i̍c̍e̍ f̍o̍r̍ s̍o̍m̍e̍ t̍i̍m̍e̍ n̍o̍w̍,̍ a̍n̍d̍ I̍ h̍a̍v̍e̍ c̍o̍m̍e̍ t̍o̍ t̍h̍e̍ c̍o̍n̍c̍l̍u̍s̍i̍o̍n̍ w̍e̍ c̍a̍n̍’̍t̍ h̍a̍v̍e̍ i̍t̍ i̍n̍t̍e̍r̍f̍e̍r̍i̍n̍g̍.̍ W̍h̍a̍t̍ u̍s̍e̍ i̍s̍ t̍h̍e̍r̍e̍ i̍n̍ s̍e̍r̍v̍i̍n̍g̍ t̍w̍o̍ m̍a̍s̍t̍e̍r̍s̍?̍ I̍ a̍m̍ s̍o̍r̍r̍y̍ y̍o̍u̍ w̍i̍l̍l̍ h̍a̍v̍e̍ t̍o̍ e̍x̍p̍e̍r̍i̍e̍n̍c̍e̍ t̍h̍i̍s̍.̍_

“...Experience what?”

Your fingers kept moving without your input, gripping the regulator, fingernails digging into your skin as your digits tightened around it. That...hurt. It felt _unpleasant_. 

With a violent wrenching motion, you pulled the device free of your body, tubing, hair-thin wires and little bits of flesh dangling from the bloody mechanism like entrails, small drops of crimson dotting the steel grates. 

You fell to your knees and screamed in agony.

Fear, _panic,_ full blown and felt for the first time in years seared through your veins. Your heart began beating a bloody staccato against your ribs, your quickening pulse causing the open wound weep blood down your hand, sticky red liquid dripping from your fingers. Tears slid down your face and you tasted salt for the first time in an age. You were scared, you were in pain, no, No, NO!

“Why did you do that!? I _needed_ that! _WHY!?_ ” you screamed at the voice.

_It was holding you back. Without it you can reach your true potential._ His voice sounded more real somehow. As if he were right next to you, and not restrained to your head. 

“Make it stop!” you sobbed. 

_Shh, shh, precious one, it is alright, you are alright._ the voice soothed, a hard hand cupping your cheek. You flinched back, looking up at...

A monster. 

He was enormous, a tall, alien figure cloaked in black shadows. He had a pale face that resembled a skull, bright lights shining like distant stars in the otherwise empty eye sockets. Cracks ran from his eyes, one up to the top of his skull, the other down to his teeth. Only partially hidden behind “lips” you could see sharp, inhuman incisors in a wide smile. His body, what you could make out, was in the vague shape of a tall human, but the darkest thing your eyes had ever perceived. Darker than the spaces between stars, as if he were a black hole from which no light could escape. 

_No, no, do not be afraid, you must calm down. Here_ , he reached out, his hand wrapped around yours. It was skeletal, all slender bones, with a hole through the palm, and absolutely _huge._ He moved your hand over the wound, pressing firmly, _Yes, very good. Apply pressure. That will slow the bleeding._

“It hurts.” you whimpered.

_Oh, I am quite certain it does. Come now, we can repair it. Up, up, on your feet, that’s it._ he encouraged, wrapping an arm around your middle and pulling you up, aiding you as you walked along the narrow hall of the ship towards the med bay.

He looked down at you, one brow bone raising minutely, _Ah, you are shaking. This is unfortunate._

“Wh-What--Why?” you stuttered, your lips feeling almost numb yet tingling.

_It means you are in shock._ One of his large hands pressed to your back, _Here, please take a deep breath for me?_ You nodded shakily, drawing in a shuddering lungful of air. _Yes, good, good. Just like that. In and out. You are doing so well._ he commended you as he led you down the dim, narrow hall.

The med bay was, like almost all areas of the ship, tiny. No bigger than a closet and crammed full of equipment. You stumbled over to a table bolted to the wall, a single chair tucked underneath. You set your bleeding forearm on the flat surface, reaching for the wall-mounted first aid kit with a trembling arm. Shaking fingers coated in blood worked uselessly at the latches.

_Here, allow me._

The long, elegant bones of his fingers lay over yours, steadying them and guiding you. With his help you managed to open the case. Neatly packaged medications, disinfectants, bandages and other healing apparatuses splayed out onto the small table, a few of the plastic-wrapped packages tumbling to the floor. 

“I-I can’t...there is a medical gel dispenser, s-somewhere...” your hand shook terribly as you fumbled through the packages, smearing bloody fingerprints on everything. 

_What a mess you are making. I believe you are looking for this?_ he pointed to a short, thick green tube with several buttons on the side.

“Y-yeah...” you stuttered, reaching for the device. You ripped the package open with your teeth and dumped the tube onto the table. Holding it like a pen, you moved the tip of the dispenser over your bleeding arm, the device shaking violently in your trembling grip. 

He wrapped his hand around yours, once again guiding you. His thumb pressed yours down, depressing the button and causing the device to dispense a clear gel over your wound as he carefully moved your hand back and forth, making several passes. You could not have managed the smooth motions on your own, your limbs trembling.

Once the last of the gel was discharged, you dropped the dispenser with a clatter onto the metal table and collapsed into the chair, your body quivering as you waited for the gel to set.

_You are still shaking._ he noted with a sympathetic look, the bones of his fingers gliding up and down your undamaged arm in a soothing gesture. 

“What are you?” you asked in a thin warble, “Is this real? Are you real??”

_Hm, that is a complicated question, especially without a basis for what constitutes reality, but I believe I can offer you some answers. I am not truly,_ **_physically_ ** _here, no. This-_ his fingers curled around your wrist and gently shook it back and forth, wiggling your hand side to side, - _Is simply your mind’s coping mechanism. What you see is not real. I am controlling your hand and arm muscles through input to your nervous system. Without that device, your brain is unfettered and free to move in whatever direction it choses. And for now, that is conjuring this vision of me as you do now._

“So you’re not...here?” 

_I do exist. I am inside you, just as I had said._ His hand slipped under to cradle yours, your hand resting flat on his hollow palm. Black liquid seeped from your skin, beading into onyx droplets that grew and spread until your entire hand was coated in darkness. You moved your fingers, gawking at the strange phenomena, until his hand curled, closing over yours, _But not in tangible quantities. Not yet. Soon, I will manifest far more of myself beyond the confines of your head, and your body, and you will experience the full extent of me._

“What if I don’t want you to?” you sniffed, trying to put up a brave front, “I don’t want you to hurt me again.”

_Sweet little thing,_ he crooned as he reached out with his other arm, the back of his hand caressing your cheek, _You haven’t a choice. But do not worry. It is in my best interest to keep you safe and whole. A good parasite needs a thriving host, after all._

You whimpered again.

_Oh, precious one, please, do not be afraid. Tell me, what are you experiencing right now?_

“Pain,” you answered immediately, “My heart is pounding and I feel lightheaded. I’m...frightened.”

_In other words, you are_ **_alive_** _, yes?_ he said eagerly, almost manically, the lights of his eyes bright and his hand holding yours tightening around your fist, _Isn’t that wonderful? To once again experience the full gamut of sensations that were denied to you? Isn’t it so_ **_freeing_ ** _?_

“No!” you snarled, snatching your hand away, “Now it’s _you_ who’s commanding me!” 

_Anger, I’ll bet it has been a good long while since you experienced that._ He chuckled darkly, _But I am not a machine, and neither are you. I will not make you an automaton no better than a simpleton obeying commands. Your feelings are your own, your desires your own. Yes, I may bend your will somewhat to suit my needs, but I promise you-_ he curled his phalanges under your jaw, tilting your head up towards his eyelights as he leaned down closer, expression so intense it managed to somehow still your trembling and seize your breath in your lungs, _-I will care for you. I will keep you safe. You are the most precious thing in the galaxy to me._

“...Alright.” you whispered, not sure what else to say in the face of such devotion. You were silent for a time, occasionally prodding at the sticky gel to test if it had cured yet. “You never said what you were.” you said to fill the silence.

_Hm? Oh, I suppose I skipped over that. I was classified as what my kind called ‘monsters’, but that term is likely not applicable anymore. Perhaps sentient void magic is more apt._

“You’re made of magic?”

_Of course, what else would I be made of?_

“Matter?” you looked over his void-black body, “...Anti-matter?”

He laughed softly again at your apparently amusing assumption, _No, no._ **_You_ ** _are made of matter, for the most part. You are animated stardust, a beautiful, breathing being, an orchestrated symphony of molecules composed into sinew and bone. And your mind! Countless neurons in an mystifying arrangement, so unique nothing in this universe could ever replicate it. Such a lovely little thing you are, it is a miracle you exist, to have found you at all, wandering this empty vastness..._

The way he spoke, breathily and voice full of wonder, it was as if he thought you really were some precious treasure. 

_But amidst all these atoms that make up you, there is magic. Not much in comparison to all that physical substrate mind you, but it gathers in quantities slightly more elevated than the ambient levels of the rest of the universe. A positive gradient, if you will. And it is your magic that I have bound myself to. It is how I can speak to you, and move you about. If I had to wager a guess, and you’ll find my guesses are often more accurate than not, the reason your scans could not detect me is because they are not attuned to magic._

“So I was never hallucinating. It was all real, just undetectable.” you said in dawning realization. 

_Remember, you are actively hallucinating my appearance currently._ he unhelpfully reminded you. You groaned, head falling forward to rest on the cool metal of the table top.

_Come now, this is nothing to be concerned over._ he said, brushing his hand over your head. You could _feel_ his hand stroking you, and how could that have been possible if he was a hallucination? _You are coping very well, all considering. Come, you should rest so that you may heal._ he tugged on your uninjured arm, prompting you to stand.

“The ship repairs-”

_That can wait. You need rest, your work will still be here when you awake._ he said firmly as he led you back down the hall, your boots noisily ringing out on the steel grating, while he silently walked beside you. 

“It isn’t time to sleep in the cycle.” you weakly objected, and he frowned.

_You are not beholden to a time table any more, do you understand? You may rest when you wish, eat when you wish, stars, I’ve never seen you do_ **_anything_ ** _for leisure._ he stopped and turned to you, his hands clasped your shoulders and he leaned down to stare into your eyes with that same unyielding intensity, those stars in his sockets twinkling, _This is your life. You must spend it as you desire. Now, would you like to rest?_

“...Yes.” you meekly replied.

_A wise choice. Let’s get you to bed._

* * *

Living without the neuroregulator was terrifying. 

It had been a leash, but a comfortable one. Now the film that kept reality distant and blurry had been peeled away, and you could see and feel everything in raw, aching, _perfect_ clarity. Every pain was amplified, as well as every joy. Eating polystarch was a horrific tactile experience while curling up in the warmth of your hammock was now bliss. 

As it turned out, you did not require as much sleep as you had been made to experience. To cut down on the resources you consumed, you had been artificially induced to slumber. That freed up quite a bit of time, and you had to find creative ways to spend those extra hours.

Your tablet held quite a few programs that you never explored, some old books and music from bygone eras, card games you played with Gaster, even a drawing application that whittled away hours as you put to digital paper new ideas that flowed through your head like a newly tapped spring. Your companion was quite pleased at this development, always encouraging you in those more creative pursuits.

_Is that what you see me as?_ he asked as you held up the tablet, studying a portrait you drew of him.

“More or less. I can’t get it any darker than this...” it was impossible to illustrate on a digital screen how his shadows seemed to swallow light. There were other strange quirks a static image couldn’t capture; He was truly an alien being, never eating, sleeping, or even making the minor motions that you identified as human; rubbing an eye when tired, fidgeting when bored, yawning, scratching an itch, _blinking._ He did none of those things, and it was unsettling. 

_It is interesting how your mind had chosen to render me._

“Is this not what you look like?” you looked up from the screen towards him, raising an eyebrow.

_It is, for the most part. But certain aspects of my appearance are quite telling._ he said with a teasing, enigmatic grin that told you he was not going to elaborate no matter how much you needled him.

Your conversations had begun to follow this pattern. You found you actually _cared_ what he had to say, wanting to learn who exactly he was, what made him tick and what led to his current condition. You asked more questions of him than ever, and sometimes he would regale you with tales of the eons he’d spent wandering the expanse of space, of supernovae and neutron stars, black holes and collisions of galaxies, but anything of his previous life he kept secreted away. You couldn’t blame Gaster for not divulging everything, as you were also careful to navigate conversations away from your past before you boarded this ship.

Late one cycle with nothing better to do, you went up to the cockpit, situated at the foremost point at the bow of the ship. There were very limited windows on the hull, most very narrow and only used to visually inspect the outermost paneling, but here the viewport was large and wide, giving you an unadulterated view of space in all it’s starlit splendor. 

_Are you still upset at me for doing this to you?_ he asked quietly as you watched the stars, his fingers trailing over the scar on your wrist.

“...I don’t know.” you answered honestly, “But I’m glad you’re here with me.”

Very gently he cupped your cheek, turning you to face him. He looked between your eyes, wearing a soft smile that, for some unknown reason, made your cheeks heat up.

“What is it?” you asked in a hushed tone.

He didn’t answer you right away, content to just look for a while, _There are stars in your eyes, love. It is a breathtaking sight._

* * *

Something strange started happening to you.

You felt restless. An agitated sort of restlessness that no amount of fidgeting or pacing would alleviate. The peculiar feeling only worsened as the cycles went on. Your face felt warm despite the ship’s frigid interior and your skin electric, like every touch was charged. The feeling was so unfamiliar and almost entirely forgotten that it took a few cycles to place exactly what it was your body was experiencing. 

Arousal. For the first time in years. 

You hadn’t touched yourself since the neuroregulator had been installed, the device controlling your hormones and muting any urge to do so. But this was something above and beyond an idle want, as if all those years of repressed sexual desire had come back with a vengeance.

You tossed and turned in your hammock, kept awake by the grating feeling of unfulfillment. 

_Can’t sleep?_ Gaster asked, ever present and watching over you. 

“No...” you groaned, rolling over again to face away from him, “Normally, I would have a device that regulates my sleep.” you said heatedly. Beyond the unsettling neediness you felt, you were also far more irritable these last few cycles.

_Hm, this again._ he sighed. His fingers trailed down your back, their bony tips felt through the micromesh jumpsuit you slept in. The sensation made your spine arch, a moan bit back as your teeth dug into your lip. God, you _ached_ for any sort of touch. You wanted to beg him to brush his fingers over your bare skin, do something, _anything,_ that would satisfy this overwhelming desire.

_Do you feel strange?_ he innocuously asked, his phalanges skimming back up, teasing along the back of your neck, his large fingers lightly circling around your throat. His bones grazing over you felt heated to the touch.

“What do you mean?”

_Do you feel an urge?_ he whispered in your ear. You felt his weight against your back, his heated body almost fevered, _This need you have, an all-consuming directive of your mind that demands-_ his arms coiled around you, pulling you close to him, **_-satisfaction._**

“I do.” The whispered admission escaped you in a breathy whine.

_I thought so._ he chuckled darkly, something wet sliding up your neck; His tongue. _I feel it too. If I had to guess, and you know well the accuracy of my guesses, removing that device returned to you the ability to feel arousal. And as we are sharing this body, that in turn awakened mine. We have here a positive feedback loop that has, if I am not mistaken, triggered my heat._

“Your what??” you gasped. He dragged his fangs over the skin of your neck, nipping and then lapping gently at your pulse point until you were panting with want.

_The desire to mate, love. Certainly the solution to this predicament is obvious._ he spoke against your skin, lips curling into a grin.

“...Are you suggesting we have sex?” you asked, astonished, then followed with a more hesitant and hushed, “Is that even possible?”

_Certainly. I have my ways._ He ground up against you like some animal bending to instinct, and you felt something hard and thick sliding against you from behind. _What say you, my precious one? Let me take you and give us both relief from this._ He growled, breath ghosting over you.

You couldn’t spare much thought to understand the mechanics of his suggestion, your blood burning, and you were so desperate for release that you all but moaned, “ _Yes._ ” He sighed against your neck in what sounded like relief.

Then suddenly he moved away, and you shivered from the absence of his body heat, twisting to face him with an almost accusatory look at leaving you cold and unfulfilled, but he met it with a measured grin. The shadows that made his body, the darkness of the void, began growing, dripping and pooling like tar below him. And from that darkness erupted sinuous shapes, tendrils that writhed like snakes and reached for you.

The tendrils curled around your legs, coiling up them like black vines. They held you fast, and you couldn’t move an inch in their powerful grip. 

“Gaster?”

_Shh, I promise I am only going to help you. You have no reason to fear me._ He smiled softly, hand cradling the back of your head as he leaned down, kissing you. It was strange, mostly teeth with those ridges of bone that served as his lips brushing against yours. But as strange as it was to kiss an alien being, it felt _good._ God, you hadn’t been touched like this in ages, and now your body was crying out for more.

You kissed him back, the shadowy creature smiling briefly before nipping at your lower lip. His fangs were sharp, biting into your flesh and just on the verge of drawing blood. _I want you to enjoy this, love,_ he said as he pulled away, voice husky with want. His hand slid up your body to your collar and slowly unziped your jumpsuit, exposing your skin to the cold air, _I will care for you, just as I promised._

More black writhing shapes slithered up your body, squirming under your clothes. They tugged away the jumpsuit, then stripped you of your underwear, leaving you completely nude. The thick tentacles once again coiled more tightly around you, wrapping around your legs, your arms, your waist before hoisting you up. You yelped as you found yourself off your feet and suspended in air.

“Gaster!” you worriedly shouted, eyes wide as you looked at him, dangling naked and helpless in his grasp. The vulnerability you felt was almost enough to recant what you’d already agreed to.

_Relax, my precious one._ He soothed, your face now level with his. Those abyssal sockets gleamed dangerously as he reached out to caress your cheek. _You want this, don’t you?_

Another tentacle rose from the dark, crawling up your leg, teasing along your thigh, moving higher until it pressed against you. It felt warm, and almost slimy, as if it were covered in a thin sheen of oil that slicked your skin. It prodded your entrance, almost teasingly.

You realized in that moment that you did want this. No, it wasn’t a _want_ but a _need_. As necessary as breathing, you felt a compulsion for him, your worries and fear overridden and nearly forgotten. 

The aching desperation felt like true madness.

“Gaster, _please!_ ” you begged.

His mouth quirked into a sinful grin. The tentacle wiggled and writhed before pushing inside, a gasp escaping you, followed by a groan. Your head lolled forward, hanging down as your body shivered from pleasure. Stars, that felt _good_ , blessedly sweet relief at the sensation of finally being filled. The tentacle began pumping in and out of you, rocking your captured form in time with the thrusts.

_You make the most exquisite expressions._ He purred delightedly, gripping your chin and lifting your head back up, directing your bleary gaze towards him. _Why, you’re hardly even looking at me. Love, we can’t have you lose focus now, this is just the beginning._

Another tentacle made its way up your thigh, sliding up beside the one already buried deep inside you. It took a moment in your dazed state of mind to catch his intentions. 

“What? I can’t--That’s too much!” you stuttered. 

_You can take it._

The second tentacle squirmed vigorously until it slid into you as well, stretching you open and pressing in deep, your loud moan echoing through the empty ship. The dark appendages stilled, giving you a moment to acclimate to the staggering sensation. His gaze slowly panned down over you, taking in the sight of you impaled on two of his tentacles. Delightedly, his eyelights flickered back up to your eyes, a fanged grin stretching across his face. 

The tentacles began moving again, alternating, one pushing into you while the other withdrew, stirring up your insides and incessantly stimulating you.

The sensation was so breathtaking, you felt like you could die right in that moment, and have it be the happiest death imaginable.

_Do you like this?_ he asked with a burning gaze as his thumb stroked your cheek.

“Yes!” you emphatically cried.

**_Tell me._ **

“I love this, oh stars, Gaster, you feel so good, I love you, I love you...” you sobbed, babbling your praises of him.

He looked so pleased by your words, and something shifted in the dark. His free hand reached down, curling around some shadowy shape. He began stroking the length of it, and you realized it was his cock, made of the same darkness as the rest of him. He groaned as he touched himself, his gleaming eyes never leaving you.

_It has been so long since I’ve felt this._

Yet another black tendril squirmed up from his shadows, this one gliding over your lips. Your gaze darted between his tentacle and his face, his eyes eagerly watching you. Your lips parted and the tentacle dove inside your mouth, sliding over your tongue. The taste of him was strange, a hint of something metallic but primarily a honey sweetness that flooded your mouth and made you drool. You could feel the almost squishy texture of his shadows, and under it cords of solid, sinewy muscles that flexed as the bizarre appendage squirmed inside your mouth, pumping into you.

He fervently fucked you from both ends, picking up the pace as your muffled moans grew louder. You couldn’t tell how long it went on, your jaw beginning to ache from being forced open by the girthy tentacle filling your mouth, but you couldn't care. You were nearly euphoric, lost to mind-breaking levels of pleasure. The tentacles taking you from behind and the one diving down your throat mercilessly pounded into you, like they were trying to meet in your middle. 

Your eyes rolled back as the overwhelming pleasure that had been building in you crested over, a shudder running down the length of your spine as you came. He didn’t let up in the least, continuing to lay claim to your helpless body.

He palmed himself, roughly fisting his cock in time with every thrust of his tentacles. _You are so beautiful right now...This is just the beginning, you know. I want to see all the ways I can make you come undone, I want to hear that sweet voice of yours begging for more._

The tentacles pushed even _deeper_ inside you, seizing for a second before they begin pulsing, overfilling you with a sticky substance. He stroked himself to completion, more of the dark spend splashing over your chest, hot over your skin as it dripped down.

The tentacles withdrew and slowly unwound themselves from around you, gently placing you into his arms as he held you close, your limbs limp and useless. He looked awestruck, like he was holding the greatest gift the galaxy could bestow. 

_I will show you just how much I love you._

* * *

You had almost non-stop sex with Gaster for the next five cycles.

Whatever heat burned through him claimed you as well, his touch a momentary balm to the desire that had completely infected you. You couldn’t get enough, and neither could he, the post-climactic bliss the most addictive, euphoric experience you’d ever lived through. And like a drug, you only wanted for more.

Despite his rough fucking, he handled your person with the utmost care once he had filled you up past overflowing. He brought you food and water, even bathed you with wet rags from a bucket gently wiped over your skin when you were too spent to even stand in the shower stall. You were permitted to rest and recuperate from each exhausting encounter, but either your need, or his, woke you from whatever slumber you could briefly manage. 

_You take me so well,_ he praised as he stood before you, hands clasped behind his back while you were held aloft by dark tendrils, his tentacle jammed down your throat, _It is as if you were meant for this. As if the galaxy forged you, a perfect being for me. Or was it the other way around?_ he mused, _Perhaps I was meant to find you, to free you and save you...Don’t you love this?_ **_Isn’t this pleasure worth it?_ **

His tentacle slithered out of your mouth and you gagged, tears streaking down your face, “Yes.” you rasped in reply, “I need you, _please,_ Gaster.”

_Oh, you are so perfect._ he breathed, almost dreamily, reaching up to cradle your face. He leaned down, kissing your bruised lips, his long black tongue delving into your mouth. He tasted every inch of you, the back of your teeth, licked the roof of your mouth, swirled against your own tongue. You were his to explore, and he never seemed to tire of it. 

With a sigh he pulled away from you, his eyelights blazing in their sockets, and you tried to chase after him, leaning as far forward as your bound limbs would allow. He smiled at your eagerness, his thumb brushing over your lower lip for a brief moment while he regarded you with a look of adoration. But then his tentacles twisted you around, bending you over and presenting you to him. His elegant fingers wandered reverently over your naked back, lightly painting the shape of galaxies over the expanse of your skin before trailing down, his phalanges curling around your hips and tugging you closer. You felt his cock grinding against you, thick and heavy. 

_How many more orgasms do you think I can wring out of you this cycle, hm? I suppose it depends on how long you remain conscious._ He bent low over you, breath tickling the hairs on the back of your neck, _I want to hear you_ **_scream_ ** _for me, so I know how much you love this._

He thrust inside you with one smooth motion, hilting himself completely.

And you screamed, crying out in pleasure, just as he commanded while he fucked you.

You forgot about your mission. You forgot about your loneliness. Stars, in those heated throes, you even forgot your own name.

But never his. His name was a mantra you recited, spoken between cries of ecstasy as he made you experience sensations you scarcely knew were possible. You extolled every wondrous feeling he brought about in an endless chant. He was the gravitational center to your existence, pulling you closer until you ignited, incandescent and insensate, and all you could see was stars. 

* * *

On the sixth cycle, the heat faded.

You slept for nearly half the cycle, curled up in your hammock and more exhausted than you could ever recall, your muscles sore and aching.

_Are you awake?_ he asked when you finally stirred, sounding tired. You didn’t think he was capable of that, but his expression was worn and his voice was threadbare.

“Yeah...Are you okay?” you asked, reaching out and lightly caressing his face. 

_I...Yes, I am._ he replied, taken aback by your touch. 

You tilted your head, confused at the reaction. “What is it?”

_I do not believe you have expressed worry for me before._ his phalanges curled around your fingers and he turned his head to kiss your inner wrist.

“You never gave me cause for concern before now.” your fingers gently squeezed his hand, “I love you.”

His brow bones shot up in surprise, _You do? Truly?_

“I said so, didn’t I?”

_Quite a few times, actually...The heat can make one say things they do not truly mean._

“Did you?”

_No._

“Neither did I.”

* * *

The ship was in a state of neglect, a half dozen unfinished repairs awaiting your practiced hand. 

You would have been more concerned about completing the mission had the journey not be so close to an end. From the main viewport, you could now see the planet, a green orb spinning through space that grew closer with each cycle.

On the final cycle of your mission you climbed to the cockpit one last time, strapping yourself to the single pilot’s chair before you initiated the landing sequence. You held Gaster's hand in a white-knuckled grip as the ship tore through the atmosphere, the viewport a blazing orange inferno until the ship slowed and you could see the alien landscape of Proxima spread out below you. 

The ship touched down, a jolt running through the freighter and metal groaning as it had to support its own weight again years after embarking on this voyage. You unclipped your seatbelt and descended down narrow metal stairs to the largest section of the ship, the final goal of your mission.

You had never once entered the cargo bay. Inside were crates and containers that held raw building materials, portable fuel cells, and countless supplies all with the sole purpose of supporting a fledgling colony that you were never meant to be a part of.

_What happens now?_ Gaster asked, looking over the vast collection.

“I don’t know. The first colonists will arrive in three solar revolutions of this planet. I was only estimated to last about 20 cycles after the mission completed. The neuroregulator would have administered a lethal dose of barbiturates once the cancer became unmanageable.” you said clinically.

He frowned in severe distaste, _Were you merely a mechanism to deliver goods to them? They force you onto a ship with a directive fully knowing you will perish in the end? What horrific creatures exist on your world?_

You did not answer, carrying on with your inspection of the supplies in silence until you checked off the all inventory on your tablet and walked back out of the cargo area. A tap on the screen and the airlock re-engaged, sealing it away and preserving it for the people who would one day land on this planet to build a world anew.

“I volunteered.” you whispered as you walked down the hallway towards the lowest level of the ship.

_...What did you say?_ he said, stopped dead in his tracks behind you.

“I volunteered. No one forced me on this ship. I chose to be here. I knew I wouldn’t feel anything once I was fitted with the neuroregulator, and I wouldn’t survive once the mission was over.”

He strode over, looking down at you with dismay, his hands clasping your shoulders as he turned you to face him, _Why would you do such a thing, my love?_

“My world is dying. It is considered very brave and heroic to volunteer for these missions, and-” you sniffed, wiping away your tears that leaked out the corners of your eyes, “I knew everyone back home would be better off without me.”

_...Oh my precious one. My love, you_ **_know_ ** _that is untrue, yes?_

You nodded, meeting his eyelights with a watery smile, “I do now.” 

He met yours with a soft smile of his own, _I am beyond grateful to have found you._

You wrapped your arms around his inky body in a tight embrace, “I’m glad you found me too. You saved me from myself, and I can’t thank you enough for that.”

* * *

The two of you stood at the base of the ship before the loading ramp. 

With a fist slamming into a large red button on a control panel, the airlock disengaged and the ramp descended slowly with a hiss and a whine of hydraulics. It hit the ground, and you apprehensively walked down, stepping foot onto a strange world. 

Surrounding you in all directions were grassy plains, blue crystalline blades of some alien flora crunching under your boots. The sky above was cloudless, an arching green expanse. In the distance, rising up from the plains like behemoths were the terraformers that preluded you, having landed themselves years ago. You squinted in the bright sunlight, breathing in unrecycled air for the first time in countless cycles.

You trembled, overwhelmed by it all.

_Do not fear, love._ Gaster said, one large hand squeezing your shoulder. He looked as out of place as you felt, the void-black being contrasting sharply against the sunlit surroundings, _Whatever may come, you are not alone._

_I will always be here for you._

**Author's Note:**

> Well that was a thing I wrote.
> 
> There is lots of blame to go around for this fic, my friend [MaximumSquish](https://archiveofourown.org/users/MaximumSquish/) for commissioning Freshie to write [Offer Me My Deathless Death](https://archiveofourown.org/works/28152189) and inspiring me to make my own Gaster in space fic, [ChaoticBiBastard](https://archiveofourown.org/users/ChaoticBiBastard/) for coming up with the Venom!Gaster idea, beta reading, and being a wonderful muse, [Sansual](https://archiveofourown.org/users/sansual/) for helpful suggestions with wording some scenes, [Juunee](https://archiveofourown.org/users/Juunee/) for tips on writing non-binary characters and the rest of the Gaster’s Followers crew for being so encouraging and supportive of my weird writing. 
> 
> The title was inspired by the music video for [Shelter](https://youtu.be/fzQ6gRAEoy0) (watch it if you haven’t already).
> 
> [Tumblr](https://fallingstarstuff.tumblr.com/).
> 
> 💙 Stay safe, and stay DETERMINED. ❤️


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